#!/bin/sh

# run from directory where this script is
cd `dirname $0`
EXAMPLE_DIR=`pwd`

# check whether echo has the -e option
if test "`echo -e`" = "-e" ; then ECHO=echo ; else ECHO="echo -e" ; fi

$ECHO
$ECHO "$EXAMPLE_DIR : starting"
$ECHO
$ECHO "This example shows how to use pw.x to calculate the total energy and"
$ECHO "the band structure of four simple systems: Si, Al, Cu, Ni."

# set the needed environment variables
. ../../../environment_variables

# required executables and pseudopotentials
BIN_LIST="pw.x bands.x"
PSEUDO_LIST="Si.pz-vbc.UPF"

$ECHO
$ECHO "  executables directory: $BIN_DIR"
$ECHO "  pseudo directory:      $PSEUDO_DIR"
$ECHO "  temporary directory:   $TMP_DIR"
$ECHO "  checking that needed directories and files exist...\c"

# check for directories
for DIR in "$BIN_DIR" "$PSEUDO_DIR" ; do
    if test ! -d $DIR ; then
        $ECHO
        $ECHO "ERROR: $DIR not existent or not a directory"
        $ECHO "Aborting"
        exit 1
    fi
done
for DIR in "$TMP_DIR" "$EXAMPLE_DIR/results" ; do
    if test ! -d $DIR ; then
        mkdir $DIR
    fi
done
cd $EXAMPLE_DIR/results

# check for executables
for FILE in $BIN_LIST ; do
    if test ! -x $BIN_DIR/$FILE ; then
        $ECHO
        $ECHO "ERROR: $BIN_DIR/$FILE not existent or not executable"
        $ECHO "Aborting"
        exit 1
    fi
done

# check for pseudopotentials
for FILE in $PSEUDO_LIST ; do
    if test ! -r $PSEUDO_DIR/$FILE ; then
       $ECHO
       $ECHO "Downloading $FILE to $PSEUDO_DIR...\c"
            $WGET $PSEUDO_DIR/$FILE $NETWORK_PSEUDO/$FILE 2> /dev/null
    fi
    if test $? != 0; then
        $ECHO
        $ECHO "ERROR: $PSEUDO_DIR/$FILE not existent or not readable"
        $ECHO "Aborting"
        exit 1
    fi
done
$ECHO " done"

# how to run executables
PW_COMMAND="$PARA_PREFIX $BIN_DIR/pw.x $PARA_POSTFIX"
BANDS_COMMAND="$PARA_PREFIX $BIN_DIR/bands.x $PARA_POSTFIX"
PLOTBAND_COMMAND="$BIN_DIR/plotband.x"
$ECHO
$ECHO "  running pw.x as: $PW_COMMAND"
$ECHO "  running bands.x as:    $BANDS_COMMAND"
$ECHO "  running plotband.x as: $PLOTBAND_COMMAND"
$ECHO

    # self-consistent calculation
    cat > si.scf.in << EOF
 &control
    calculation = 'scf'
    restart_mode='from_scratch',
    prefix='silicon',
    pseudo_dir = '$PSEUDO_DIR/',
    outdir='$TMP_DIR/'
    verbosity='high'
 /
 &system
    ibrav=  2, celldm(1) =10.20, nat=  2, ntyp= 1,
    ecutwfc =18.0,
    input_dft='HSE'
    nqx1=2, nqx2=2, nqx3=2
    nbnd=8
 /
 &electrons
    mixing_mode = 'plain'
    mixing_beta = 0.7
    conv_thr =  1.0d-8
 /
ATOMIC_SPECIES
 Si  28.086  Si.pz-vbc.UPF
ATOMIC_POSITIONS alat
 Si 0.00 0.00 0.00
 Si 0.25 0.25 0.25
K_POINTS automatic
 2 2 2 1 1 1
ADDITIONAL_K_POINTS tpiba_b
  5
   L 20
   gG 20
X 0
   1.0 1.0 0.0 30
   gG  1
EOF
    $ECHO "  running the scf calculation for Si...\c"
    $PW_COMMAND < si.scf.in > si.scf.out
    check_failure $?
    $ECHO " done"

# post-processing for band structure
cat > si.bands.in << EOF
 &bands
    prefix  = 'silicon'
    outdir = '$TMP_DIR/'
    filband = 'sibands.dat'
    lsym=.false.,
 /
EOF
$ECHO "  running the post-processing for band structure...\c"
$BANDS_COMMAND < si.bands.in > si.bands.out
check_failure $?
$ECHO " done"

# plotband.x
cat > si.plotband.in << EOF
sibands.dat
-10 20 3 74
sibands-p.dat


EOF
$ECHO "  running plotband.x to generate sibands.ps...\c"
$PLOTBAND_COMMAND < si.plotband.in > si.plotband.out
check_failure $?
$ECHO " done"




